Wireless networking is currently among the most rapidly expanding sectors of telecommunications and computer technology. Modern wireless networking offers excellent connectivity, convenience, and the reliability that consumers have come to expect from their everyday devices. Everything from cars to personal audio devices contains the ability to communicate wirelessly with other devices. However, the static allocation of preset channel widths employed in many wireless networks has a variety of undesirable limitations.
Currently, a great deal of wireless communication today involves the use of channels with preset widths. A wireless channel is the frequency spectrum block over which nodes transmit; it is uniquely specified by its center frequency and channel width (expressed in Hertz). The use of preset channel widths is a direct result of how the available spectrum is divided by existing wireless technologies. For example, in 802.11 (Wi-Fi) b/g, the total available spectrum block is divided into 11 overlapping channels that have a channel width of 20 MHz each and the center frequencies are separated by 5 MHz. At any given time, a Wi-Fi node communicates over one of these channels. In some cases, such as WiMax, the spectrum block is divided into channels having different widths. Yet, even in systems such as WiMax the channel width is statically assigned.
The use of preset channel widths can be highly inefficient. Additionally, fixed channel width systems must balance increasing range and reducing power consumption. The range can be increased by increasing transmission power or using lower modulation. Using lower modulations does not change the instantaneous power, but increasing transmission power increases power consumption. Moreover, the transmission range of fixed channel width systems is inherently limited, because the FCC limits the total transmission power of Wi-Fi radios. Consequently, a substantial need exists for a system that provides for adaptive control of channel widths for improved wireless networking.